bitmap_xor
description
Syntax
BITMAP BITMAP_XOR(BITMAP lhs, BITMAP rhs, ...)
计算两个及以上输入bitmap的差集，返回新的bitmap.
example
mysql> select bitmap_count(bitmap_xor(bitmap_from_string('2,3'),bitmap_from_string('1,2,3,4'))) cnt;
+------+
| cnt |
+------+
| 2 |
+------+
mysql> select bitmap_to_string(bitmap_xor(bitmap_from_string('2,3'),bitmap_from_string('1,2,3,4')));
+----------------------------------------------------------------------------------------+
| bitmap_to_string(bitmap_xor(bitmap_from_string('2,3'), bitmap_from_string('1,2,3,4'))) |
+----------------------------------------------------------------------------------------+
| 1,4 |
+----------------------------------------------------------------------------------------+
MySQL> select bitmap_to_string(bitmap_xor(bitmap_from_string('2,3'),bitmap_from_string('1,2,3,4'),bitmap_from_string('3,4,5')));
+---------------------------------------------------------------------------------------------------------------------+
| bitmap_to_string(bitmap_xor(bitmap_from_string('2,3'), bitmap_from_string('1,2,3,4'), bitmap_from_string('3,4,5'))) |
+---------------------------------------------------------------------------------------------------------------------+
| 1,3,5 |
+---------------------------------------------------------------------------------------------------------------------+
MySQL> select bitmap_to_string(bitmap_xor(bitmap_from_string('2,3'),bitmap_from_string('1,2,3,4'),bitmap_from_string('3,4,5'),bitmap_empty()));
+-------------------------------------------------------------------------------------------------------------------------------------+
| bitmap_to_string(bitmap_xor(bitmap_from_string('2,3'), bitmap_from_string('1,2,3,4'), bitmap_from_string('3,4,5'), bitmap_empty())) |
+-------------------------------------------------------------------------------------------------------------------------------------+
| 1,3,5 |
+-------------------------------------------------------------------------------------------------------------------------------------+
MySQL> select bitmap_to_string(bitmap_xor(bitmap_from_string('2,3'),bitmap_from_string('1,2,3,4'),bitmap_from_string('3,4,5'),NULL));
+---------------------------------------------------------------------------------------------------------------------------+
| bitmap_to_string(bitmap_xor(bitmap_from_string('2,3'), bitmap_from_string('1,2,3,4'), bitmap_from_string('3,4,5'), NULL)) |
+---------------------------------------------------------------------------------------------------------------------------+
| NULL |
+---------------------------------------------------------------------------------------------------------------------------+keywords
BITMAP_XOR,BITMAP